Synthesis of polyaniline/graphite composite as a cathode of Zn-polyaniline rechargeable battery

The characteristics of polyaniline/graphite composites (PANi/G) have been studied in aqueous electrolyte. PANi/G films with different graphite particle sizes were deposited on a platinum electrode by means of cyclic voltammetry. The film was employed as a positive electrode (cathode) for a Zn-PANi/G secondary battery containing 1.0 M ZnCl2 and 0.5 M NH4Cl electrolyte at pH 4.0. The cells were charged and discharged under a constant current of 0.6 mA cm(-1). The assembled battery showed an open-circuit voltage (OCV) of 1.55 V. All the batteries were discharge to a cut off voltage of 0.7 V Maximum discharge capacity of the Zn-PANi/G battery was 142.4 Ah kg(-1) with a columbic efficiency of 97-100% over at least 200 cycles. The mid-point voltage (MPV) and specific energy were 1.14 V and 162.3 Wh kg(-1), respectively. The constructed battery showed a good recycleability. The structure of these polymer films was characterized by FTIR and UV-vis spectroscopies. Electrochemical impedance spectroscopy, (EIS) was used as a powerful tool for investigation of charge transfer resistance in cathode material. The scanning electron microscopy (SEM) was employed as a morphology indicator of the cathodes. (c) 2007 Elsevier B.V. All rights reserved.